Reel mowers having one or more reel cutting units are well known for cutting grass on a turf surface. Each reel cutting unit includes a rotatable cutting reel that pushes blades of uncut grass against a sharpened bedknife to cut the blades of grass using a shearing action between the reel blades and the bedknife. A rotatable turf groomer is also known for use on the cutting unit adjacent to the cutting reel for performing one or more additional actions on the turf surface during the mowing operation for promoting the healthy growth of the grass on the turf surface. These additional actions may comprise dethatching of the turf surface, cutting horizontal runners of grass, working a fertilizer or top dressing material into the turf surface, aerating the turf surface, and the like.
Some turf groomers can be driven in a bidirectional manner to rotate either in the same direction or in a counter direction to the direction of rotation of the cutting reel. The user can select which direction of rotation of the turf groomer is used at any given time to customize the action of the turf groomer to the type and condition of the grass in the turf surface. However, in known bidirectional turf groomers, the turf groomer rotates in the same speed in either direction. In these types of bidirectional single speed turf groomers, the Applicants have discovered that the action of the turf groomer is too aggressive on the grass when rotating in a direction that is the same as the direction of forward motion of the cutting unit (the counter direction mode of operation of the turf groomer) and ends up cutting or grooming the grass in the turf surface more than is strictly needed. The Applicants have further discovered that this wastes power and is thus less efficient than would be desirable.
In addition, reel cutting units used on different mowers or different reel cutting units used on the same mower may couple the drive motors to different ends of the reel shaft due to spacing or other issues. Since the turf groomer is driven from the end of the reel shaft that is opposite to the end coupled to the drive motor, this means the drive for some turf groomers has to come off the left end of the reel shaft while the drive for the other turf groomers has to come off the right end of the reel shaft. Thus, many turf groomers are built in two different models to permit either a left hand or right hand drive of the turf groomer to accommodate the variation in how reel cutting units are driven. However, the need for two different models of turf groomers for this reason increases manufacturing complexity thus increasing manufacturing costs and the retail costs of such turf groomers. This is disadvantageous to the manufacturer and to the end user customers.